With the downscaling of semiconductor devices in recent years, lithography using EUV (Extreme UltraViolet) light which has a shorter wavelength is considered instead of conventional lithography using ArF light. However, flare (scattered light) of the exposure using the EUV light undesirably is exceedingly high. As a result, there are cases where the dimensions of the pattern that is formed undesirably has fluctuation exceeding the tolerance range due to the flare.